Fingerprint sensors are sometimes used as “navigation tools”, for example to move a cursor or pointer on a display or to perform selections of items presented on a display etc.
To be able to use a fingerprint sensor for such a navigation tool application, it is necessary to somehow track movement of the finger of a user across the fingerprint sensor.
According to one approach, described in U.S. Pat. No. 6,408,087, ridges and pores of a fingerprint are identified and motion of the ridges and pores between successive images of the fingerprint is detected.
To make the hardware of a fingerprint-based navigation tool low cost and power efficient it is desirable to decrease the fingerprint sensor size as much as possible and to use methods with low requirements on memory and computational complexity.
With that aim, U.S. Pat. No. 7,064,743 discloses a finger movement tracking method based on block matching.
However, there still appears to be room for improvement regarding estimation of a finger movement using a fingerprint sensor, in particular concerning how to achieve sufficient accuracy when using a small fingerprint sensor and tracking methods with low requirements on memory and computational complexity.